Dengue virus (DV) infection causes a spectrum of disease ranging from self-limited Dengue Fever to lifethreatening Dengue Hemorrhagic Fever/Dengue Shock Syndrome. The mechanisms of immune protection and pathogenesis are poorly understood, but DV nonstructural protein 1 (NS1) likely plays a key role. NS1 is present in the cytoplasm and on the surface of infected cells and is secreted in a soluble form (sNS1) that circulates in blood, where high sNS1 concentration correlates with increased disease severity. In vitro, sNS1 can activate complement, bind to infected and uninfected cells, and increase viral output from infected hepatoma cells. However, it is unclear if or how sNS1 affects viral dissemination or disease progression in vivo. Similarly, the role of antibodies (Abs) against NS1 is unclear due to the lack of appropriate in vivo models. Anti-NS1 Abs display protective activity against neurovirulent death in mice, but the effects of anti-NS1 Abs on DV infection of more relevant peripheral tissues have never been characterized. Nonetheless, NS1 is included in several DV vaccines under development, including that of our collaborator, Hawaii Biotech, Inc., and no test exists to evaluate the repertoire of Abs generated by either natural infection or vaccination. We have shown that DV infection of interferon receptor-deficient mice reproduces key features of human DV infection, including susceptibility to all four DV serotypes with relevant infection kinetics, appropriate tissue and cellular tropism, sNS1 circulation in the blood, thrombocytopenia correlated with viral load, and fatal vascular leak syndrome. We will use this mouse model to examine the functions of sNS1 and the effects of anti-NS1 Abs on DV infection. We will also use sera obtained from mice, prospective studies of dengue in Nicaragua, and dengue vaccine trials to generate in vitro assays to assess the repertoire of anti-NS1 Abs in infected mice, primary and secondary natural DV infections, and vaccine recipients.
In Specific Aim 1, we will assess the localization and function of sNS1 during DV infection in mice and fatal human dengue cases.
In Specific Aim 2, the effects of anti-NS1 Abs on peripheral DV infection in mice will be evaluated. We will measure the ability of both polyclonal Abs and MAbs against NS1 to protect against DV infection using both NS1 vaccination and MAbs against DV2 NS1, and we will screen for any detrimental in vivo effects of NS1 Abs. Finally, in Specific Aim 3, we will characterize the repertoire of anti-NS1 Abs generated by DV infection and vaccination and will develop in vitro tests to detect anti-NS1 Abs in human serum likely to have protective or pathogenic effects during subsequent DV infection. Together, these results will both elucidate mechanisms of DV pathogenesis and contribute to the development of a safe and effective dengue vaccine.

Public Health Relevance

Although dengue virus (DV) nonstructual protein 1 (NS1) is produced by most vaccines in clinical trials, it is not clear if anti-NS1 Abs contribute to protection or pathogenesis. Also, the function of NS1 in vivo is not well defined. We propose to characterize the cellular targets and functions of sNS1 in vivo, the effect of anti-NS1 Abs on DV infection and pathogenesis, and the repertoire of anti-NS1 Abs elicited by natural DV infection and vaccination in mice and humans. In addition, our mouse model allows questions regarding dengue immunity and pathogenesis, as well as evaluation of candidate therapeutics and vaccines, to be addressed.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Specialized Center--Cooperative Agreements (U54)
Project #
Application #
Study Section
Special Emphasis Panel (ZAI1-DDS-M)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of California Irvine
United States
Zip Code
Torres, Rodrigo; Lan, Benson; Latif, Yama et al. (2014) Structural snapshots along the reaction pathway of Yersinia pestis RipA, a putative butyryl-CoA transferase. Acta Crystallogr D Biol Crystallogr 70:1074-85
Houghton, Raymond L; Reed, Dana E; Hubbard, Mark A et al. (2014) Development of a prototype lateral flow immunoassay (LFI) for the rapid diagnosis of melioidosis. PLoS Negl Trop Dis 8:e2727
Strotmeier, Jasmin; Mahrhold, Stefan; Krez, Nadja et al. (2014) Identification of the synaptic vesicle glycoprotein 2 receptor binding site in botulinum neurotoxin A. FEBS Lett 588:1087-93
Koellhoffer, Jayne F; Dai, Zhou; Malashkevich, Vladimir N et al. (2014) Structural characterization of the glycoprotein GP2 core domain from the CAS virus, a novel arenavirus-like species. J Mol Biol 426:1452-68
Bennett, Shannon N; Gu, Se Hun; Kang, Hae Ji et al. (2014) Reconstructing the evolutionary origins and phylogeography of hantaviruses. Trends Microbiol 22:473-82
Burtnick, Mary N; Brett, Paul J; DeShazer, David (2014) Proteomic analysis of the Burkholderia pseudomallei type II secretome reveals hydrolytic enzymes, novel proteins, and the deubiquitinase TssM. Infect Immun 82:3214-26
Koskiniemi, Sanna; Garza-Sánchez, Fernando; Sandegren, Linus et al. (2014) Selection of orphan Rhs toxin expression in evolved Salmonella enterica serovar Typhimurium. PLoS Genet 10:e1004255
Sabouri, Amir H; Marcondes, Maria Cecilia Garibaldi; Flynn, Claudia et al. (2014) TLR signaling controls lethal encephalitis in WNV-infected brain. Brain Res 1574:84-95
Vigant, Frederic; Hollmann, Axel; Lee, Jihye et al. (2014) The rigid amphipathic fusion inhibitor dUY11 acts through photosensitization of viruses. J Virol 88:1849-53
Relman, David A (2014) "Inconvenient truths" in the pursuit of scientific knowledge and public health. J Infect Dis 209:170-2

Showing the most recent 10 out of 317 publications